How much can I safely over-torque lug bolts?
 

Finally got a nice floor jack so I can do my own snow changeovers.

Both my W210 and W211 have newer/shorter lug bolts (thankfully). I have two torque wrenches: an inexpensive click type (Great Neck) and a Craftsman beam type.

Did the W210 this morning. Tightened according to correct pattern first to 70 ft. lbs. then to 80 using the click wrench. Then I went around and checked with the beam wrench. Some bolts, as I hit 80, seemed to tighten a bit more.

I'm not a shop with periodically calibrated high quality torque wrenches...just a guy in a driveway. I'm more concerned about safety than over-torquing a bolt. Yet I am well aware of the headache and expense of overtorquing a bolt to the point where the head breaks off.

So the W210 spec is 80 and the W211 is 96. If I wanted, for the sake of safety to exceed the values by a little bit, what would anyone recommend? Or should I simply trust my wrenches and get it as exact as I can?

I'd use the factory recommended torque. The wrenches are probably close enough.

X2 what Tom said....
the real problems come with people using pneumatic tools.... if you are using your arms and a normal length click or bar to tighten it... very unlikely of any problems...
I am just glad you are following the book as far as you are....
The main thing is when starting out take all the bolts in by finger while jiggling the wheel... once all are tightened that way... and the wheel clearly against the hub in a level fashion... then go to what you are doing....

The way you did the job was really good.

You allowed the wheel to "find its place" as you fitted it and then checked with the torque wrenches you have.

I agree with above: As you compared the values between two wrenches the chances are good that your torque wrenches are close enough.

Thanks guys. Basically what I did is gently snugged them with wheel off the ground with a regular wrench according the star pattern. Then, once the wheel was on the ground, did 70 then 80. But the jiggling advice makes sense.